An access network is a part of a communications network which connects subscribers to a service provider. Fiber to the x (“FTTx”) typically refers to a fiber-to-the premises broadband network architecture that uses an optical fiber to replace all or part of the metal local loop used for last mile telecommunications. In FTTx networks, information is typically transmitted in downstream direction at 1490 nm wavelength and in upstream direction at 1310 nm wavelength.
Gigabit Passive Optical Network (“GPON”) and Active Ethernet technologies are two popular alternatives to provide triple-play services (e.g., voice, video, and data) to users in FTTx networks. GPON and Active Ethernet are both technologies which allow transmission over optical fiber. The GPON and Active Ethernet technologies, however, are significantly different from each other.
FIG. 1A shows a typical passive optical network (“PON”) for use in FTTx. As shown in FIG. 1A, PON 100 is a point-to-multipoint architecture, which includes an optical line terminal (“OLT”) 101 that may be located at a Central Office (“CO”) connected to a set of optical network terminals (“ONTs”) 103 that may be located at the customer premises through a feeder fiber 102, an optical power splitter 104, and individual distribution fibers 105. Information is typically transmitted downstream 106 from OLT 101 to each of ONTs 103, upstream 107 from each of the ONTs 103 to OLT 101 on feeder fiber 102 by using a time division multiplexing scheme, in which dedicated transmission time slots are granted to each individual optical network terminal of ONTs 103 to avoid data collisions.
FIG. 1B shows a typical Active Ethernet architecture 110 for use in FTTx. As shown in FIG. 1B, Active Ethernet architecture 110 is a point-to-point architecture, which includes an optical line terminal (“OLT”) 111 and a set of optical network terminals (“ONTs”) 113 located at the customer premises. Each of the ONTs 113 is connected to the OLT 111 directly through its own distribution fiber 115. Data may be transmitted downstream 116 from OLT 111 to each of the ONTs 113, and upstream 117 from each of the ONTs 113 to OLT 111. As shown in FIG. 1B, the fiber is not shared among multiple ONTs 113.
In conventional systems, a physical layer (e.g., transceivers, fibers, and/or any other optics) typically cannot be shared by the different network protocols—e.g., by GPON and Active Ethernet protocols. For example, transmitting data in upstream direction in a steady state PON can typically disrupt all other network interface devices due to the time division multiplexing (“TDM”) nature of upstream transmission in the point-to-multipoint case. It typically is difficult to reliably determine without manual intervention which networking protocol is currently used in an access network. Sharing the physical layer among different protocols without reliably knowing which protocol is appropriate for use may corrupt transmission of information.